Piston type pump

ABSTRACT

A piston type pump having a cylinder sleeve mounted in a pump cartridge assembly for insertion and removal with the cartridge assembly from a bore in the pump casing. The cartridge assembly has a head portion extending across the outer end of the casing bore and a sleeve portion integral with the head portion, and the cylinder sleeve is pressed into the sleeve portion to provide a wear liner for the pump piston. Outlet passage means and outlet check valve means are provided in the head portion of the cartridge to control discharge of fluid from the pump, and inlet passage means and inlet check valve means are provided in the pump piston to control intake of fluid.

United States Patent [15] 3,682,572 Yarger [4 1 Aug. 8, 1972 [54] PISTONTYPE PUMP 3,496,880 2/ 1970 Woltf ..417/273 I t I 2,450,248 9/1948Morgan et al. ..4l7/273 [72] mgjg fi jgif g 683 Tmber 2,461,235 2/1949Raymond ..417/273 [22] Filed: July 27, 1970 Primary Examiner-William L.Freeh [211 App. No; 58,529 Attorney-McCanna, Morsbach, Pillote & Muir[57] ABSTRACT [52] US. Cl ..4l7/273, 417/454 51 Int. Cl. ..F04b 49/00F04b l/08 type Pump havmg a cylmde' f [58] Field of Search ..417/273, 451, 269, 567; m P f' assembly 3 92/169 removal Wllhlhe cartridge assemblyfrom a bore in the pump casing. The cartridge assembly has a headportion extending across the outer end of the casing [56] ReferencesCited bore and a sleeve portion integral with the head por- UNTTEDSTATES PATENTS tion, and the cyliinder sleeve is pgessig into the sleeveportion to provi e a wear mer or e pump piston. 3,292,554 12/1966Hessler ..4l7/269 Outlet passage means and Outlet check valve means2,683,423 7/1954 Raymond ..4l7/273 are provided in the head portion fthe cartridge to 2,945,444 7/ 1960 Lel ssner ..41'7/269 controldischarge of fluid from the pump and inlet 2,941,475 6/1960 Blair..4l7/269 passage means and inlet check valve means are vided in thepump piston to control intake of fluid. eemmg e 1,775,975 9/ 1930Swainson ..4l7/454 4 Claim, 2 Drawing Figures 4/ v 3 l7 Illa 41 22 I3153 3; 1 SI l2 ob W 3 a 7 1 j) Z 1;; 54 I5 25.1 M: i3

1/ 31 70 4a A 8/ 25b 25 93 /T v 3/ 7" 53 y) 55 slat PATENTED 3 I97?3.682.572

7 7777:, mgatul W eya PISTON TYPE PUMP BACKGROUND OF THE INVENTION Thepump cylinders in piston type pumps are subject to wear and it hasheretofore been proposed, as disclosed in the U. S. Pat. to Yarger No.2,675,759, to mount a cylinder sleeve in the pump casing to provide awear liner which can be removed and replaced when it becomes worn.However, such cylinder sleeves must fit tightly in the casing to preventleakage of fluid and it is frequently difficult to remove a worncylinder sleeve from the pump casing.

SUMMARY OF THE INVENTION In the present invention, cylinder sleeveswhich form wear liners for the pump piston are mounted cartridge bodiesfor insertion and removal as a unit therewith. The cartridge assembliesinclude a unitary cartridge body having a cartridge bore extendingaxially thereinto from its inner end and defining a cylinder portion atthe inner end of the cartridge body and an integral head portion at theouter end, and the cylinder sleeves extend into the inner end of thecylinder portion of the cartridge body and have a radially tight fit inthe cartridge bore to seal the interface between the cylinder sleeve andthe cartridge body. This arrangement enables use of cartridge bodiesformed of a material which can be different from the materials utilizedfor the pump casing and which cartridge body material is advantageouslyselected to provide the desired strength characteristics forwithstanding the relatively high pressures commonly employed in pistonpumps. The cylinder sleeve is advantageously formed of a materialdifferent from the material in the cartridge body and selected toprovide the desired wear characteristics. Moreover, with thisarrangement, the volumetric displacement of the pump can be varied overa relatively wide range without changing the dimensions of the pumpcasing or cartridge body, it being only necessary to change the internaldiameter and hence the wall thickness of the cylinder sleeves, and tocorrespondingly change the diameter of the pump pistons which fit in thecylinder sleeves. Outlet check valves are advantageously provided in thehead portion of the cartridge assemblies to control flow of fluid fromthe pump and the cartridge assemblies can be arranged to deliver thefluid axially from the outer end of the cartridge body to a deliveryline or laterally of the cartridge body into discharge passages formedin the pump casing. The outer end of the cylinder sleeve isadvantageously spaced from the adjacent end of the cartridge bore in thecartridge body to provide an annular recess at the inner end of thecylinder sleeve, and the inner of the cylinder sleeve is advantageouslylocated intermediate the inner and outer limits of travel of the outerend of the pump piston to prevent formation of a ridge on the piston orcylinder sleeve due to wear.

Various important objects of this invention are to provide an improvedpiston type pump in which a cylinder sleeve wear liner is mounted in aremovable cartridge to facilitate servicing and repair of the pump andreplacement of the cylinder sleeve when necessary; in which the cylindersleeve and cartridge body can be formed of relatively differentmaterials selected to provide the desired wear characteristics andstrength characteristics in the sleeve and cartridge respectively;

in which the volumetric displacement of the pump can be varied over awide range without changing the dimensions of the pump casing orcartridge body; and in which a multiple piston type pump embodying theinvention can be readily adapted for single or plural discharges.

These, together with other objects, features and ad vantages of thepresent invention will be more readily understood by reference to thefollowing description when taken in connection with the accompanyingdrawings wherein:

FIG. 1 is a sectional view through a multiple piston pump embodying thepresent invention and taken on the plane 11 of FIG. 2; and

FIG. 2 is a sectional view taken on the plane 2-2 of FIG. 1.

In the embodiment of the invention illustrated in the accompanyingdrawings, the pump is of the radial piston type having three radiallydisposed pistons an gularly spaced apart, it being understood that thenumber of pistons employed can be varied and may be more or less thanthe number illustrated and that the piston arrangement can also bevaried and may, for example, comprise a series of aligned pistonsoperated from a cam shaft, or an axial piston pump.

In general, the pump includes a casing 10 defining a chamber 11 andhaving a plurality of casing bores 12 which communicate at their innerend with the chamber 11 and which open at their outer ends at the outerside of the casing. The casing can conveniently comprise a casting and,in the radial piston type pump illustrated, the casing has a centralportion 10a that defines the chamber 11 and outwardly extending portions10b which have the casing bores 12 formed therein. Pump cartridgeassemblies designated l3a-13c are disposed in the casing bores 12, whichpump cartridge assemblies have a similar construction and like numeralsare used to designate corresponding parts. The pump cartridge assemblieseach comprise an elongated generally cylindrical body having an outerdiameter dimensioned to fit in a casing bore 12 and the cartridge bodiesare removably secured in the casing bores as by threads 14 formed on theinner end of the cartridge body and casing bore. The cartridge bodieshave a cartridge bore 15 extending axially inwardly from the inner endof the cartridge body to form a cylinder portion 16 at the inner end ofthe cartridge body and a head portion 17 at the outer end, which headportion extends across the outer end of the casing bore. Outlet passagemeans and outlet check valve means are provided in the head portion ofthe cartridge and, for this purpose, a stepped bore is formed in thehead portion to provide an inner reduced diameter passage 18 and anaxially outer passage 19 of larger diameter with a tapered shoulder 20therebetween to provide a valve seat. A check valve, conveniently in theform of a ball 21 is provided in the enlarged passage 19 and cooperateswith the shoulder or seat 20 to control flow through the outlet passage.A lightweight spring 22 may be provided to yieldably urge the ball check21 to its closed position.

The pump casing and cartridge assemblies are arranged so that, with aminor change in the cartridge assembly, the pump can be adapted foreither single or plural discharges. In the embodiment illustrated, one

cartridge assembly 13a is arranged so as to deliver its output flow toone utilization circuit and the other cartridge assemblies 13b and 13care arranged to deliver their combined flows to a second utilizationcircuit. As best shown in FIG. 1, the pump casing has a cored dischargepassages formed therein and arranged to communicate withthe casing bores12 adjacent their outer ends. In order to make the pumpcasinguniversally adaptable for either single ormultiple discharges, allof the discharge passages in the casing are arranged to intercommunicatewith each other and, as shown, include a first discharge passage 25ahaving one end communicating with one casing bore 12 adjacent the outerend of the cartridge assembly 13a; a second discharge passage 25b havingone end communicating with another casing bore 12 adjacent the outer endof g the cartridge assembly 13b; a third discharge passage 25 ccommunicating with yet another casing bore adjacent the outer end of thecartridge assembly 130; and a fourth discharge passage 25d thatcommunicates with the first-mentioned casing bore 12 adjacent the outerend of the cartridge assembly 134. As will be seen from FIG. 1,discharge passages 25a and 25b communicate with each other and with adischarge fitting 26a. Discharge passages 25c and 25d also communicatewith each other and with a second discharge fitting 26b. In addition,provision is made for intercommunicating discharge passages 25a and 25dso that all discharge passages intercommunicate with each other to allowdischarge of fluid to either of the discharge outlets 260 or 26b. In theembodiment shown, only one discharge outlet 26a is utilized and theother is closed as by a plug 27.

The cartridge assemblies 13a-13c are each formed with a peripheralgroove 31 located to communicate with the respective discharge passages25a-25d and provision is made for sealing the cartridge body to thecasing at points inwardly and outwardly of the peripheral groove 31. Forthis purpose, a first O-ring seal 32 is disposed in a groove in theperiphery of the cartridge bodies inwardly of the grooves 31 and asecond O-ring type seal 33 is provided between the head portion of thecartridge and the casing, outwardly of the groove 31. The second O-ringseal 32 is similar to an SAE fitting and comprises an O-ring disposed ina counterbore 34 at the outer end of the casing bore 12, which O-ring isclamped by a beveled shoulder 35 on the head portion of the cartridgebody. With this arrangement, the cartridge bodies are sealed to thecasing inwardly and outwardly of the groove 31 so as to prevent leakageof pump discharge fluid both inwardly toward the chamber 11 andoutwardly toward the outside of the casing.

As previously pointed out, the cartridge assemblies can be adapted toeither deliver separate flows or combined flows through the dischargepassages 25a-25c. In the form shown, one cartridge assembly 13a isarranged for individual delivery and, for this purpose, has a dischargefitting 41 mounted as by threaded engagement with the outer end of thecartridge assembly 13a. The fitting 41 has a delivery passage 41a formedtherein to communicate with the outlet passage 19 in the cartridgeassembly and the fitting 41 is conveniently counterbored as indicated at41b at its inner end to provide a seat for the spring 22. Fitting 41 isadapted for connection to one fluid utilization circuit 43 which may, asdiagrammatically shown in F IG. 1, include a flow reversing valve 44 anda fluid actuator 45. A separate relief valve 46 may .be provided in theutilization circuit 43 and, as shown, the relief valve 46 and the returnoutlet of valve 44 are connected through a return line 47 to a reservoir48. I

The other cartridge assemblies 13b and 130 are herein shown arranged todeliver their combined output to the discharge passages 25a-25c. Forthis purpose, the outer ends of the bores '19 are closed as by plugs 51convenientlycounterbored as shown at 510 at their inner ends to form aguide and seat for the springs 22. Lateral passages 53 areprovided inthe cartridge assemblies 13b and 130 to communicate the outlet passages19 in the cartridge assemblies, after the check valves 41b therein, withthe peripheral groove 31 so as to allow discharge of fluid fromthecartridge assemblies 13b and 13c into the aforementioned dischargepassages 25a-25c. Discharge passages 25a-25c are connected to a secondfluid utilization circuit 54 herein diagrammatically shown as includinga flow reversing valve 55 and a fluid actuator 56.

A built-in relief valve is advantageously provided in the pump casingfor the casing discharge passages 25a-25. As shown in FIG. 2, the reliefvalve includes relief passages 60 and 61 which respectively communicatewith one of the casing bores 12 adjacent the outer end thereof andwiththe chamber 11. The casing has an enlarged counterbore 62 aligned withthe passage 60 and defining a relief valve seat 63 therebetween and arelief valve, conveniently in the form of a ball 64 is yieldably pressedagainst the seat as by a relief valve spring 65. The pressure exerted onthe relief valve spring can be selectively adjusted as by the threadedscrew 66 to thereby adjust the operating pressure of the relief valve.As also shown in FIG. 2, an inlet passage 68 is provided in the pumpcasing 10 and is adapted for connection as by a fitting 69 to an inletline i 70 leading to the supply reservoir 48.

Cylinder sleeves are mounted in the cartridge bores 15 to provide a wearliner for the pump pistons 76. The cylinder sleeves 75 are formed of amaterial, such as cast iron selected to provide the desired wearcharacteristics and are fitted tightly in the cartridge bores to sealthe interface therebetween. The cylinder sleeves are preferablypress-fit in the cartridge bores with their inner ends substantiallycoterminous with the inner end of the cartridge body, but with the outerend 75a of the cylinder sleeves spaced axially from the adjacent end 15aof the cartridge bore to provide an annular recess in the cartridge bodyat the outer ends of the cylinder sleeves. In order to prevent theformation of a wear ridge on either the cylinder sleeve or piston 76during operation of the pump, the outer end 75a of the cylinder sleeveis located intermediate the inner and outer limits of travel of theouter end 760 of the piston whereby the outer end of thepiston movesoutwardly of the end 75a of the cylinder sleeve during extension of thepump piston as shown in cartridge 13a, and thereafter moves back intothe cylinder sleeve as the piston is retracted, as shown in cartridges13b and 130.

The pump pistons 76 are cyclically reciprocated by an actuator, hereinshown in the form of a cam ring 81 mounted on an eccentric cam 82 drivenby a shaft 83. As best shown in FIG. 2, the shaft is rotatably supportedas by bearings 84 and 85 on the pump casing, and a shaft seal 86 isprovided for sealing the interface between the shaft and the pumpcasing.

Fluid inlet passage means and inlet check valve means are provided inthe pump pistons to admit fluid from the supply chamber 11 into themotive chamber between the piston and the head of the cartridge. Thepistons have a head portion 91 that engages the cam ring 81 and thefluid inlet passage includes an axially disposed passage 92 thatcommunicates through lateral passages 93 with the supply chamber 11. Thepiston is counterbored at 94 to provide an annular seat 95 around theinlet passage 92 and a check valve, herein shown in the form of a ball96 cooperates with the seat to control inflow of fluid to the motivechamber. In the preferred embodiment illustrated, the pistons 76 areformed with a skirt 97 at their outer ends which skirt is preferablysufficiently thin to radially expand under the fluid pressure conditiondeveloped during the working stroke of the piston, to assure a tightseal between the piston and the cylinder sleeve. Piston return springs99 are conveniently interposed between the pistons and the head portionof the cartridge and, as shown, the head portion of the cartridge iscounterbored at 98 to provide a centering recess for the return springs99, while the other end of the return springs engage an apertured plate100 seated on a shoulder in the piston. The plate 100 is spaced from theseat 95 a distance sufficient to allow the check valve 96 to open duringthe return stroke of the piston. The inlet check valves will normallyclose when working stroke of the piston begins. However, if desired, aninlet check valve spring (not shown) can be provided between the inletcheck valve ball 96 and the plate 100. As shown in FIG. 1, the outer endof the skirt 97 is preferably internally chamfered to provide a thinouter edge on the piston which can be radially expanded by the fluidpressure during the working stroke of the piston to assure a tight sealbetween the piston and the cylinder sleeve.

From the foregoing it is thought that the construction and operation ofthe piston pump will be readily understood. The cylinder sleeves providewear liners for the pistons and are mounted in cartridges for removal asa unit therewith from the pump casing. Thus, when a cylinder sleevebecomes worn or when it is otherwise necessary to service a pumpassembly, the cartridge can be removed from the pump casing and thecylinder sleeve replaced if necessary. Since the cylinder sleeve issupported by the cartridge, the material from which the cylinder sleeveis formed can be selected to provide the desired wear characteristicsand the cartridge made of a different material such as cold rolled steelto provide the desired strength characteristics in the cartridge forwithstanding high pump discharge pressures. Moreover, since thecartridges effectively form selfcontained pumping units, the pumpcasing-can itself be formed of a relatively low strength material suchas aluminum. The cylinder sleeves, when press-fit in the cartridgebores, have their outer ends spaced from the adjacent end of thecartridge bore to provide a relief recess I at the outer end of thecylinder sleeves. Moreover, the ends of the cylinder sleeves are locatedintermediate the inner and outer limits of travel of the outer ends ofthe piston so that formation of a ridge on either the cylinder sleeve orpiston during use is effectively avoided.

While the embodiment of the present invention as herein disclosedconstitutes a presently preferred form, it is to be understood thatother forms might be adopted coming within the scope of the appendedclaims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as fol: lows:

l. A piston type pump comprising:

a. a pump casing defining a fluid supply chamber and at least oneaxially elongate casing bore having an inner end communicating with thesupply chamber and an outer end opening at the outer side of the casingremote from the supply chamber;

b. a pump cartridge assembly having means removably mounting the same insaid casing bore for assembly and removal as a unit therefrom, saidcartridge assembly including:

l a cartridge body having a cartridge bore extending axially thereintofrom its inner end and defining a cylinder portion at the inner end ofthe cartridge body and a head portion at the outer end of the cartridgebody, said head portion having outlet passage means thereincommunicating with the cylinder portion and an outlet check valve insaid outlet passage means arranged to open for flow from the cylinderportion and to close to prevent return flow, and

2 a cylinder sleeve formed of a material different from the material ofthe cartridge body and disposed entirely within the inner end of saidcylinder portion of the cartridge body for radial support thereby andhaving a radially tight fit in the cartridge bore to seal the interfacetherebetween, said cylinder sleeve having the outer end thereof spacedfrom the adjacent end of the cartridge bore to form an annular recess atthe outer end of the cylinder sleeve,

0. a pump piston slidable in said cylinder sleeve defining a motivechamber between the piston and the head portion of the cartridge body,said piston having inlet passage means communicating the supply chamberwith the motive chamber and inlet check valve means in the inlet passagemeans arranged to open for flow of fluid into the motive chamber; and

d. piston actuator means in said supply chamber operatively engagingsaid pump piston to cyclically reciprocate the same.

2. A piston pump according to claim 1 wherein said outer end of thecylinder sleeve is located intermediate the limits of travel of theouter end of the pump piston during reciprocation of the latter.

3. A piston pump according to claim 1 wherein said piston has athin-walled skirt portion at the axially outer end thereof, saidcylinder sleeve having the outer end thereof located intermediate thelimits of travel of the outer end of the piston during reciprocation ofthe latter.

4. A piston type pump according to claim 1 wherein said casing hasdischarge passage means communicating with the casing bore adjacent theouter end of the inner end thereof threadedly engaging the pump boreinwardly of said fluid discharge passage means in the casing andanoutwardly extending shoulder on the cartridge body at the outer endthereof engaging the pump casing around the pump bore.

3 l i i l

1. A piston type pump comprising: a. a pump casing defining a fluidsupply chamber and at least one axially elongate casing bore having aninner end communicating with the supply chamber and an outer end openingat the outer side of the casing remote from the supply chamber; b. apump cartridge assembly having means removably mounting the same in saidcasing bore for assembly and removal as a unit therefrom, said cartridgeassembly including: 1 a cartridge body having a cartridge bore extendingaxially thereinto from its inner end and defining a cylinder portion atthe inner end of the cartridge body and a head portion at the outer endof the cartridge body, said head portion having outlet passage meanstherein communicating with the cylinder portion and an outlet checkvalve in said outlet passage means arranged to open for flow from thecylinder portion and to close to prevent return flow, and 2 a cylindersleeve formed of a material different from the material of the cartridgebody and disposed entirely within the inner end of said cylinder portionof the cartridge body for radial support thereby and having a radiallytight fit in the cartridge bore to seal the interface therebetween, saidcylinder sleeve having the outer end thereof spaced from the adjacentend of the cartridge bore to form an annular recess at the outer end ofthe cylinder sleeve, c. a pump piston slidable in said cylinder sleevedefining a motive chamber between the piston and the head portion of thecartridge body, said piston having inlet passage means communicating thesupply chamber with the motive chamber and inlet check valve means inthe inlet passage means arranged to open for flow of fluid into themotive chamber; and d. piston actuator means in said supply chamberoperatively engaging said pump piston to cyclically reciprocate thesame.
 2. A piston pump according to claim 1 wherein said outer end ofthe cylinder sleeve is located intermediate the limits of travel of theouter end of the pump piston during reciprocation of the latter.
 3. Apiston pump according to claim 1 wherein said piston has a thin-walledskirt portion at the axially outer end thereof, said cylinder sleevehaving the outer end thereof located intermediate the limits of travelof the outer end of the piston during reciprocation of the latter.
 4. Apiston type pump according to claim 1 wherein said casing has dischargepassage means communicating with the casing bore adjacent the outer endof the latter, said outlet passage means in the cartridge body openinglaterally of the cartridge body after the check valve means tocommunicate with said discharge passage means, said means removablymounting the cartridge assembly in the pump bore includes threads on theouter periphery of the cartridge body at the inner end thereofthreadedly engaging the pump bore inwardly of said fluid dischargepassage means in the casing and an outwardly extending shoulder on thecartridge body at the outer end thereof engaging the pump casing aroundthe pump bore.